There's also plenty on the line for WWE, and a lot of it comes down to Hulk Hogan's popularity. Hogan hasn't played much of a role in the in-ring build-up of this weekend's action, but he may be the night's most important player because, when it comes to WrestleMania, the casual fan is key.

Just consider that last year WWE took home revenue of $67 million, or about 16% of its total gross, from pay-per-view buys. WrestleMania alone was accountable for $28 million, or more than 40%, of that revenue stream; the 11 other PPV events averaged around$3.5 million each. That April surge in PPV buys is, in large part, the result of not-so-serious fans returning to the fold for WWE's version of the Super Bowl.

And thus WWE caters to those casual fans, having previously turned to celebrities like Mr. T and Lawrence Taylor. The only way that this year's event can hope to match or surpass the records set by 2012's WrestleMania 28 (more on that in a bit), is Hulk Hogan's star power. To really understand why, we need to first look back on recent history.

WWE has been a publicly traded company since October 1999, but for the first few years the company didn't clearly break out its WrestleMania pay-per-view buys. So far as I can tell, WWE only began providing hard numbers in 2004, when some 886,000 fans bought WrestleMania XX. Over the next few years, those WrestleMania buys climbed to a then-record 1.2 million in 2007.

The WrestleMania buy rate then gradually fell to a six-year low 900,000 in 2010, after which it rebounded. Two years of strong growth - including a record 1.3 million buys in 2012 - was followed by a slight dip last year.

The same pattern holds for revenue associated with pay-per-view buys. WWE has only broken out its WrestleMania pay-per-view revenue since 2007, when it took home $24.6 million on the then-record 1.2 million buys. That income dropped to a low of $20.5 million in 2010, and bounced back to a record $30.1 million in 2012:

The most obvious reason for the dip in viewership from 2007 to 2010 is the economic recession. In short, people who suddenly found themselves out of work were far less inclined to drop $60 on a wrestling pay-per-view event.

But that doesn't explain how viewership managed to hit an all-time high while unemployment was still at 9%, or why it then dropped off in 2013 despite an improved economy. Those changes are easily explained, however, by what WWE was putting in the ring.

The main event of 2010's WrestleMania 26 was a bout between Shawn Michaels and the Undertaker, a rematch from the previous year's WrestleMania that had Michaels' career on the line. It was an exciting match, especially for fans who had followed the story over the previous year, but it ultimately featured two guys who had been at every WrestleMania since 2003. That year's 900,000 PPV buys were the fewest for a WrestleMania since 2004.

Compare that to the following year. WrestleMania 27's main event was a pretty weak showdown between The Miz and John Cena, yet the event's PPV buys jumped more than 20% to 1.1 million. The key difference? Dwayne Johnson, aka The Rock, who returned after seven years away from the ring to play guest host (and then interfere in the main event). It was a factor of star power. The dedicated fans were going to tune in one way or the other, but the return of The Rock, a childhood favorite of many former or casual fans, was clearly enough to boost viewership.

That importance of star power also explains how WrestleMania 28, with its main event between The Rock and Cena, arguably the two biggest stars of their respective generations, wound up setting records for PPV buys (1.3 million) and revenue ($30.1 million). Given that success, there's little question why WWE brought The Rock back the following year for another main-event match against Cena. The staleness of the showdown probably played a role in viewership dropping a tick last year, but the $28 million in pay-per-view revenue is still WWE's second-highest all-time.

This year, Hulk Hogan has made a triumphant return to WWE as WrestleMania's guest host, the role The Rock played back in 2011. Hogan helped usher in the WrestleMania era, having competed in the main event of eight of the first nine WrestleManias. Hogan isn't on the card this time around - though there are three mystery entrants in the battle royal - but "his presence will be felt," according to Paul Levesque, who wrestles as Triple H and also oversees WWE's talent and live events. WWE ought to hope so, because Hogan is the key to drawing in the casual fans who aren't joining WWE's new subscription network.